Catalyst for producing an olefin from an alcohol, method for producing olefin, polyolefin, and olefin oxide

ABSTRACT

Disclosed are a catalyst for producing, from an alcohol, an olefin whose number of carbon atoms is at least one more than the number of carbon atoms of the alcohol, wherein at least the surface of the catalyst is substantially composed of zirconium oxide; a method for producing an olefin using the same; and so on.

TECHNICAL FIELD

The present invention relates to a catalyst for producing an olefin froman alcohol and a method for producing an olefin using the catalyst. Thepresent invention also relates to a polyolefin and an olefin oxide eachof which is produced using, as a raw material, an olefin obtained by theforegoing method.

BACKGROUND ART

In the field of the recent production of chemical raw materials, for thepurposes of suppressing the emission of carbon dioxide and preparing fordrying up or a rise in prices of petroleum resources in the future, itis demanded to convert the chemical raw materials from petroleum-basedresources into non-edible biomasses. In particular, there is required atechnology capable of efficiently producing polypropylene that is arepresentative general-purpose resin, from bioethanol that is a biomassresource. As for a method for producing propylene from ethanol, forexample, Non-Patent Document 1 and Patent Document 1 describe methodsusing a zeolite catalyst having zirconium supported thereon.

PRIOR ART DOCUMENT Non-Patent Document

-   Non-Patent Document 1: Catalysis Letters (2009) 131:364-369

Patent Document

-   Patent Document 1: JP-A-2010-202612

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

However, according to the methods described in Non-Patent Document 1 andPatent Document 1, since a catalyst composed mainly of a zeolite isused, large quantities of an alkane and BTX components (e.g., benzene,toluene, and xylene) are formed as by-products, and hence, theselectivity to an olefin lowers. In consequence, the development of atechnology capable of producing an olefin selectively and efficiently iseagerly demanded.

In view of the foregoing problem, the present invention has been made,and an object thereof is to provide a catalyst and a method forproducing, from an alcohol, an olefin whose number of carbon atoms ismore than the number of carbon atoms of the alcohol selectively andefficiently. In addition, another object of the present invention is toprovide a polyolefin and an olefin oxide, each of which is producedusing, as a raw material, an olefin produced by the foregoing method.

Means for Solving the Problem

In order to solve the foregoing problem, the present inventors madeextensive and intensive investigations. As a result, it has been foundthat zirconium oxide is very effective as a catalyst component capableof producing, from an alcohol as a raw material, an olefin whose numberof carbon atoms is at least one more than the number of carbon atoms ofthe alcohol selectively and efficiently and that at least the surface ofa solid catalyst is substantially composed of zirconium oxide, leadingto the accomplishment of the present invention. Specifically, thepresent invention is as follows.

[1] A solid catalyst for producing, from an alcohol, an olefin whosenumber of carbon atoms is at least one more than the number of carbonatoms of the alcohol, wherein

at least the surface of the catalyst is substantially composed ofzirconium oxide.

[2] The catalyst as set forth in [1], wherein the whole of the catalystis substantially composed of zirconium oxide.[3] The catalyst as set forth in [1] or [2], wherein the alcohol isethanol, and the olefin is propylene.[4] The catalyst as set forth in any one of [1] to [3], wherein thezirconium oxide has a structure of either a tetragonal crystal or acubic crystal.[5] A method for producing an olefin including an olefin formation stepof forming, from an alcohol, an olefin whose number of carbon atoms isat least one more than the number of carbon atoms of the alcohol,wherein

in the olefin formation step, the alcohol is brought into contact withthe catalyst as set forth in any one of [1] to [4] at a temperature offrom 300° C. to 700° C.

[6] The method for producing an olefin as set forth in [5], wherein thealcohol contains water in an amount of not more than 7 times the molarnumber of the alcohol.[7] The method for producing an olefin as set forth in [5] or [6],wherein the alcohol is brought into contact with the catalyst at a gaugepressure of 50 kPa or more.[8] The method for producing an olefin as set forth in any one of [5] to[7], wherein the alcohol is ethanol, and the olefin is propylene.[9] A polyolefin produced using, as a raw material, an olefin producedby the method as set forth in any one of [5] to [8].[10] An olefin oxide produced using, as a raw material, an olefinproduced by the method as set forth in any one of [5] to [8].

Effect of the Invention

According to the present invention, it is possible to provide a catalystand a method capable of producing, from an alcohol, an olefin whosenumber of carbon atoms is at least one more than the number of carbonatoms of the alcohol selectively and efficiently. In addition, it ispossible to provide a polyolefin and an olefin oxide, each of which isproduced using, as a raw material, an olefin produced by the foregoingmethod.

Modes for Carrying Out the Invention

A solid catalyst for producing an olefin of the present invention(hereinafter also referred to as “catalyst for olefin production of thepresent invention” or “catalyst of the present invention”) and a methodfor producing an olefin, and also a polyolefin and an olefin oxide aredescribed below, but the present invention is not limited to thefollowing descriptions.

In addition, when a numerical range is expressed by the symbol “-” inthe present specification, this range shall include a lower limit valueand an upper limit value.

[1. Catalyst for Olefin Production]

The catalyst for olefin production of the present invention is a solidcatalyst for producing, from an alcohol, an olefin whose number ofcarbon atoms is at least one more than the number of carbon atoms of thealcohol, wherein at least the surface of the catalyst is substantiallycomposed of zirconium oxide.

It is meant by the terms “at least a surface is substantially composedof zirconium oxide” as referred to herein that a proportion (area ratio)of zirconium oxide on the surface is 50% by area or more. The area ratioof zirconium oxide is preferably 70% by area or more, and morepreferably 100% by area (the case where the whole is zirconium oxide).It is meant by the terms “the area ratio of zirconium oxide is 100% byarea” as referred to herein that the whole of the surface of thecatalyst is composed of zirconium oxide.

For example, in the case where the raw material is ethanol, and thedesired product is propylene, so long as only zirconium oxide exists asa reaction active catalytic species, propylene is selectively formed onthe zirconium oxide from ethanol through acetone. On the other hand, inthe case where there coexists another component, for example, a catalystcomponent having strong acidity such as a sulfate, ethylene formed by adehydration reaction of ethanol is polymerized to form an oligomer, anda decomposition reaction in which the protonated oligomer is decomposedin various ways through skeletal isomerization and β-cleavage proceeds.Thus, the reaction according to the present invention is hindered, andvarious products are formed without forming mainly propylene asdescribed above.

In consequence, it is preferable that the catalyst surface issubstantially constituted of only zirconium oxide.

Examples of the form of the catalyst of the present invention includesupported catalysts and oxide catalysts. A carrier of the case of thesupported catalyst is not particularly limited, and examples thereofinclude silica, alumina, titania, magnesia, calcia, graphite, and thelike. In the case where the carrier is exposed on the surface, suitableexamples thereof include those having low dehydration ability againstthe alcohol which is used as the raw material, such as silica,α-alumina, and graphites. The loading of zirconium oxide is preferably51% by mass or more, and more preferably 70% by mass or more. Inaddition, examples of the oxide catalyst include such forms as azirconium oxide powder and a zirconium oxide molding. In the case of thezirconium oxide powder, the particle diameter thereof after sieving ispreferably from 0.01 to 2 mm, and more preferably from 0.1 to 1 mm. Inthe case of the molding, when a rectangular parallelepiped which iscircumscribed on the molding is supposed, the maximum length of thesides of the rectangular parallelepiped is preferably from 0.5 to 20 mm,and more preferably from 1 to 10 mm.

Examples of the type of the crystal structure of zirconium oxide includea tetragonal crystal, a cubic crystal, a monoclinic crystal, or anamorphous structure. Of these, the zirconium oxide which is applied tothe present invention is preferably a tetragonal crystal or a cubiccrystal. When the zirconium oxide is a tetragonal crystal or a cubiccrystal, the selectivity to the desired olefin increases, so that theyield can be increased.

Though the alcohol which is allowed to react with the catalyst of thepresent invention is not particularly limited, a primary alcohol havingthe number of carbon atoms of from 2 to 12 is preferable. Examples ofthe primary alcohol having the number of carbon atoms of from 2 to 12include ethanol, 1-propanol, 1-butanol, isobutanol, 1-pentanol,1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, and1-dodecanol. Above all, a primary alcohol having the number of carbonatoms of from 2 to 8 is preferable, and a primary alcohol having thenumber of carbon atoms of from 2 to 4 is more preferable. So long as theprimary alcohol having the number of carbon atoms of from 2 to 12 isconcerned, the selectivity to the olefin can be enhanced.

Furthermore, it is more preferable to use ethanol derived from abiological resource (biomass) as the alcohol to be applied to thepresent invention. Unlike the case of using ethanol obtained from afossil fuel, the olefin can be produced without increasing carbondioxide in the environment by using bioethanol for the reactionaccording to the present invention.

In addition, though the olefin to be produced varies depending upon thealcohol which is allowed to react, it is preferably propylene. Inconsequence, it is preferable to use the catalyst of the presentinvention at the time of producing propylene using ethanol as a rawmaterial.

The method for producing the catalyst of the present invention is notparticularly limited, and it is possible to apply various knownproduction methods. Commercially available products can also be used solong as they are a material in which at least the surface thereof issubstantially composed of zirconium oxide.

In the case where the catalyst of the present invention is a supportedcatalyst, it can be fabricated by supporting a zirconium oxide precursoron the carrier as previously described by an impregnation method or thelike and then properly performing calcination (for example, at from 300to 900° C.)

In the case where the catalyst of the present invention is an oxidecatalyst, for example, it can be produced by fabricating a zirconiumoxide precursor-containing precipitate, performing filtration andcalcination (for example, at from 300 to 900° C.), and then properlyperforming sieving, molding treatment, or the like.

Here, examples of a raw material of the zirconium oxide precursorinclude zirconium(IV) acetylacetonate ((CH₃COCHCOCH₃)₄Zr), zirconium(IV)n-butoxide (Zr(OC₄H₉)₄), zirconium(IV) tert-butoxide (Zr(OC₄H₉)₄),zirconium(IV) n-propoxide (Zr(OC₃H₇)₄), zirconium(IV) iso-propoxide(Zr(OCH(CH₃)₂)₄), zirconium(IV) ethoxide (Zr(OC₂H₅)₄), zirconium(IV)carbonate n-hydrate (Zr(CO₃)₂.nH₂O), zirconium(IV) oxide dichloriden-hydrate (ZrCl₂O.nH₂O), zirconium(IV) chloride (ZrCl₄), zirconium(IV)bromide (ZrBr₄), and zirconium(IV) dinitrate oxide n-hydrate (Zr0(NO₃)₂.nH₂O).

[2. Production Method of Olefin]

The method for producing an olefin of the present invention is a methodincluding an olefin formation step of forming, from an alcohol, anolefin whose number of carbon atoms is at least one more than the numberof carbon atoms of the alcohol, wherein in the olefin formation step,the alcohol is brought into contact with the catalyst for olefinproduction of the present invention at a reaction temperature of from300° C. to 700° C.

Incidentally, details of the alcohol and the olefin are those aspreviously described.

The alcohol which is used in the present invention preferably containswater in an amount of not more than 7 molar times the molar number ofthe alcohol, more preferably contains water in an amount of from 0.5 to7 molar times the molar number of the alcohol, still more preferablycontains water in an amount of from 0.5 to 6 molar times the molarnumber of the alcohol, and especially preferably contains water in anamount of from 1 to 5 molar times the molar number of the alcohol.

In the case where the alcohol which serves as the raw material isethanol, examples of the olefin to be formed include propylene,1-butene, cis-2-butene, trans-2-butene, isobutene, and pentene inaddition to ethylene; and in the case where the alcohol serving as theraw material is 1-propanol, examples of the olefin to be formed includepentenes, hexenes, and octenes in addition to propylene.

Above all, the olefin to be formed is preferably propylene. In thatcase, in the method for producing an olefin of the present invention, itis especially preferable that propylene is selectively produced usingethanol as the raw material.

In the olefin formation step, the method for bringing the alcohol intocontact with the catalyst of the present invention is not particularlylimited, and it is allowable to merely introduce the alcohol into acontainer filled with the catalyst.

Examples of a reactor for carrying out the olefin formation step includea fixed bed reactor, a fluidized bed reactor, a batch type reactor, anda semi-batch type reactor. From the viewpoint of the productivity of theolefin, a fixed bed reactor or a fluidized bed reactor is preferable,and a fixed bed reactor is more preferable.

Though the form of the alcohol which serves as the raw material is notparticularly limited, from the viewpoints of increasing the formationefficiency of an olefin and making it easy to perform the reaction, itis preferable that the alcohol is a gas at the time of contact with thecatalyst.

In addition, at the time of bringing the alcohol in a gaseous state intocontact with the catalyst in a container, the alcohol may also be fed incombination with other components into the container.

Examples of such other components include a nitrogen gas, water vapor,hydrogen, carbon monoxide, carbon dioxide, the entirety or part of aproduct recovered from an outlet of the reactor, and a carrier gas otherthan those described above which is substantially unreactive with thealcohol which serves as the raw material and the olefin to be formed.

Though the amount of the catalyst used is not particularly limited, itis preferably from 0.000002 tons to 0.02 tons per ton of the alcohol. Inaddition, the feed rate of the alcohol may be, for example, from 0.002tons/h to 200 tons/h, and preferably from 0.02 tons/h to 20 tons/h perton of the catalyst.

In addition, though the temperature at which the alcohol which serves asthe raw material is brought into contact with the catalyst in the olefinformation step is not particularly limited so long as it is in the rangeof from 300 to 700° C., it is preferably from 350 to 600° C. Byperforming the reaction at a temperature falling within this range, itis possible to prevent a lowering of the selectivity of the olefin.

In addition, the reaction pressure in the olefin formation step ispreferably a gauge pressure of 50 kPa or more, more preferably a gaugepressure of 150 kPa or more, still more preferably a gauge pressure offrom 150 to 20,000 kPa, and especially preferably a gauge pressure offrom 450 to 1,000 kPa. Here, the gauge pressure refers to the pressureexpressed on the basis of atmospheric pressure, and the value obtainedby adding the atmospheric pressure to the gauge pressure is the absolutepressure.

The contact time between the alcohol and the catalyst is notparticularly limited, and for example, in the case of performingcalculation while reducing the volume of the raw material used for thereaction into that of a gas at 25° C. and 1 atm, the contact time isfrom 0.001 seconds to one hour, and preferably from 0.1 seconds to oneminute.

In addition, it is preferable that the yield of the olefin whose numberof carbon atoms is at least one more than the number of carbon atoms ofthe alcohol serving as the raw material is higher. The yield of theolefin is preferably 1% or more, more preferably 5% or more, and stillmore preferably 10% or more.

Here, the yield of the olefin can be determined by {(the number of molesof carbon of the olefin formed, whose number of carbon atoms is at leastone more than the number of carbon atoms of the alcohol)/(the number ofmoles of carbon of the alcohol used for the reaction)×100(%)}.

[3. Polyolefin and Olefin Oxide]

The polyolefin of the present invention is produced by polymerizing theolefin obtained by the previously described method for producing anolefin of the present invention. The polyolefin represented bypolypropylene is inexpensive and excellent in mechanical properties, andtherefore, it is used as a structural material in a wide field.

Examples of the method for the production of such a polyolefin include amethod in which an olefin or an olefin mixture is allowed to react in agas phase or liquid phase in the presence of a polymerization catalyst;and a method in which after the polymerization to form a single polymer,another olefin or olefin mixture is polymerized. Preferred examples ofthe polyolefin include a homopolymer of propylene; a random copolymer ofpropylene and ethylene; and a polypropylene-based composition obtainedby producing a homopolymer of propylene in a first step and producing arandom copolymer of propylene and ethylene in a second step.

In addition, the olefin oxide of the present invention is produced by,for example, oxidizing the olefin obtained by the previously describedmethod for producing an olefin of the present invention. An olefin oxiderepresented by propylene oxide is industrially important as anintermediate raw material for industrial chemicals, synthetic resins,rubbers, and the like. Examples of the method for the production of suchan olefin oxide include a method in which an olefin is brought intocontact with a peroxide in the presence of a catalyst for olefin oxideproduction; and a method in which a chlorohydrin is produced from anolefin and chlorine, and the chlorohydrin is brought into contact with abase such as calcium hydroxide.

EXAMPLES

Embodiments of the present invention are described in more detail belowby illustrating Examples. As a matter of course, the present inventionis not limited to the following Examples, and various forms regardingthe details can be made.

Example 1 (1) Preparation of Catalyst A:

A zirconium oxide powder (RC-100, available from Daiichi Kigenso KagakuKogyo Co., Ltd.) was subjected to particle size regulation into a sizeof from 0.3 to 0.6 mm by means of sieving, thereby obtaining a catalystfor olefin production. This catalyst is hereinafter referred to as“Catalyst A”.

Incidentally, it was confirmed from a powder X-ray diffraction patternof Catalyst A that the crystal structure thereof was a monocliniccrystal.

(2) Production of Propylene:

0.50 g of Catalyst A was filled in a quartz tube having across-sectional area of 0.85 cm², and an ethanol/nitrogen mixed gashaving an ethanol concentration of 33% by volume was fed at a rate of 11mL/min into the reaction tube and allowed to react at atmosphericpressure and 400° C. (contact time: 2.8 seconds). A gas discharged froma gas exhaust port of the reaction tube was analyzed by means of gaschromatography to determine the yield and the formation rate ofpropylene. The analysis results obtained are shown in the followingTable 1.

Comparative Example 1 (1) Preparation of Catalyst B:

A catalyst in which nickel was supported on a carrier made of silica wasprepared according to the method described in WO 2007/083684 A. Thepreparation of the catalyst was performed according to the followingprocedures.

306 g of colloidal silica (SNOWTEX (registered trademark) 20, availablefrom Nissan Chemical Industries, Ltd.), 225 g of dodecyl trimethylammonium bromide, 71 g of a 4N sodium hydroxide aqueous solution, and705 g of ion-exchanged water were mixed, and the mixture was heated at140° C. for 48 hours while allowing it to stand. Subsequently, theresultant was filtered, and a filtration residue was dried, affording adried material.

8 g of the dried material was add to 80 g of ion-exchanged water, towhich was then added a solution of 1.1 g of nickel nitrate hexahydratedissolved in 81 g of ion-exchanged water, and the mixture was heated at80° C. for 20 hours. Thereafter, the resultant was filtered, and afiltration residue was dried and heated in air at 550° C., therebyobtaining Ni-MCM41. This catalyst is hereinafter referred to as“Catalyst B”.

It was confirmed from a powder X-ray diffraction pattern that theobtained Catalyst B had a hexagonal structure, and the Catalyst B had aBET surface area of 844 m²/g and a nickel concentration of 3.6% by mass.

(2) Production of Propylene:

Propylene was produced in the same manner as that in Example 1, exceptfor using Catalyst B in place of the Catalyst A. The results are shownin the following Table 1.

TABLE 1 Catalyst Catalyst Reaction weight volume temperature C3′ yieldC3′ formation rate Catalyst (g) (mL) (° C.) (%) (g-C3′ h⁻¹ mL-cat⁻¹)Example 1 Catalyst A 0.50 0.50 400 13 0.066 Comparative Catalyst B 0.502.0 400 10 0.013 Example 1

Incidentally, in Table 1, “C3′” denotes propylene (the same applieshereinafter); the yield of “C3′ yield” is defined by {(the number ofmoles of carbon in propylene formed)/(the number of moles of carbon inthe alcohol used for the reaction)×100(%)}; and “C3′ formation rate”denotes the mass of propylene formed for one hour per mL of thecatalyst.

As shown in the foregoing Table 1, in Example 1, the weight (yield) ofpropylene formed for one hour per mL of the catalyst was greatly large,as compared with Comparative Example 1.

Example 2 (1) Preparation of Catalyst C:

A zirconium oxide powder (RSC-HP, available from Daiichi Kigenso KagakuKogyo Co., Ltd.) was subjected to particle size regulation into a sizeof from 0.18 to 0.3 mm by means of sieving, thereby obtaining a catalystfor olefin production. This catalyst is hereinafter referred to as“Catalyst C”.

(2) Production of Propylene:

1.00 g of Catalyst C was filled in a quartz tube having across-sectional area of 0.83 cm². 3 mL/min of an ethanol gas, 3 mL/minof nitrogen, and 6 mL/min of water as water vapor were fed, respectivelyinto the reaction tube and allowed to react under a gauge pressure of500 kPa at 450° C.

180 minutes after starting the ethanol feed, a gas discharged from a gasexhaust port of the reaction tube was analyzed by means of gaschromatography to determine the conversion of ethanol and the yield ofthe product. The results are shown in Table 2.

In Table 2, “EtOH” denotes ethanol; “H₂O” denotes water; “C3′” denotespropylene; “C2′” denotes ethylene; “C2” denotes ethane; “C2s” denotesethylene+ethane; “C3” denotes propane; “C3s” denotes propylene+propane;“C4s” denotesisobutene+1-butene+trans-2-butene+cis-2-butene+1,3-butadiene+n-butane+isobutane;and “BTX” denotes benzene+toluene+o-xylene+m-xylene+p-xylene (the sameapplies hereinafter).

Incidentally, the yield of each product is defined by {(the number ofmoles of carbon in each product in the outlet of the reaction tube)/(thenumber of moles of carbon of ethanol used for the reaction)×100(%)}(hereinafter the same).

The conversion is defined by {1−(number of moles of carbon of ethanolafter the reaction)/(number of moles of carbon of ethanol fed)×100(%)}(the same applies hereinafter).

Comparative Example 2 (1) Preparation of Catalyst D:

Zr-modified ZSM-5 (80) was fabricated by adopting the method describedin Catalysis Letters (2009), pp. 364-369.

Specifically, 3 g of NH₄ type ZSM-5 (CBV8014, available from ZeolystInternational, Inc.) was added to an aqueous solution of ZrO(NO₃)₂.2H₂O(0.13 g) dissolved in 40 mL of pure water (zirconium/aluminum molarratio=0.4), and the mixture was dried at 50° C. by an evaporator andfurther dried at 100° C. for 5 hours. Thereafter, the resultant wascalcined in air at 540° C. for 4 hours, affording Zr-modified ZSM-5(80).

The Zr-modified ZSM-5 (80) was subjected to particle size regulationinto a size of from 0.18 to 0.3 mm by means of sieving, therebyobtaining a catalyst for olefin production. This catalyst is hereinafterreferred to as “Catalyst D”. A zirconium concentration in Catalyst D was1.5% by weight. Incidentally, since Catalyst D has a surface area of 431m²/g and a zirconium concentration of 1.5% by weight, assuming thatzirconium oxide forms a monomolecular layer (in that case, the areabecomes maximum), the surface area of zirconium oxide contained in 1 gof Catalyst D will become not more than 21 m², namely the surface areaof zirconium oxide will become not more than 5% of the surface area ofCatalyst D according to calculations.

(2) Production of Propylene:

The same operations as those in Example 2 were followed, except forusing 1.00 g of Catalyst D, and the conversion of ethanol and the yieldof the product were determined. The results are shown in the followingTable 2.

Comparative Example 3 (1) Preparation of Catalyst E:

0.50 g of spherical alumina (KHO-12, available from Sumitomo ChemicalCo., Ltd.) was pulverized and classified into a size of from 0.3 to 0.6mm, thereby obtaining a catalyst for olefin production. This catalyst ishereinafter referred to as “Catalyst E”.

(2) Production of Propylene:

Catalyst E was filled in a quartz tube having a cross-sectional area of0.85 cm², and an ethanol/nitrogen mixed gas having an ethanolconcentration of 33% by volume was fed at a rate of 11 mL/min into thereaction tube and allowed to react at atmospheric pressure and 450° C. Agas discharged from a gas exhaust port of the reaction tube was analyzedby means of gas chromatography to determine the conversion of ethanoland the yield of each product. The results are shown in the followingTable 2.

TABLE 2 Reaction pressure H₂O/EtOH Conversion C3′/C3s C2′/C2s Yield/(%)(C-mol base) Catalyst (kPaG) (mol/mol) (%) (mol/mol) C2′ + C3′ C3′ C3C2′ C2 C4s BTX Example 2 Catalyst C 500 2 100 0.998 0.996 84.6 31.9 0.152.7 0.2 0.3  0.03 Comparative Catalyst D 500 2 100 0.036 0.153 2.1 1.232.4 0.9 5.0 13.2 27.27 Example 2 Comparative Catalyst E 0 0 100 0.9970.998 92.5 1.1 0.004 91.4 0.2 2.8 Not Example 3 measured

As compared with Catalyst D in which the surface is not substantiallyconstituted of zirconium oxide and Catalyst E that is a solid acidcatalyst, Catalyst C which corresponds to the present invention was highin the selectivity to an olefin whose number of carbon atoms is at leastone more than the number of carbon atoms of ethanol.

Example 3

1.02 g of Catalyst C was filled in a quartz tube having across-sectional area of 0.071 cm². 2 mL/min of an ethanol gas, 2 mL/minof nitrogen, and 0 mL/min, 2 mL/min, 10 mL/min, 20 mL/min, or 30 mL/minof water as water vapor were fed, respectively into the reaction tubeand allowed to react at atmospheric pressure and 410° C. A gasdischarged from a gas exhaust port of the reaction tube was analyzed bymeans of gas chromatography to determine the conversion of ethanol andthe yield of propylene. The results are shown in the following Table 3.

TABLE 3 Total Flow rate Flow H₂O/EtOH C3′ flow rate of EtOH rate of H₂Oratio Conversion yield (mL/min) (mL/min) (mL/min) (mol/mol) (%) (%) 6 20 0 100 9.6 8 2 2 1 100 19.0 16 2 10 5 100 25.0 26 2 20 10 97.0 21.3 362 30 15 83.0 10.8

From Table 3, the C3′ (propylene) yield became high with an increase ofthe ratio of water. As a result, taking the results of the conversioninto consideration, it may be considered that the case where theH₂O/EtOH ratio is in the vicinity of 5 is most practically useful.

Example 4

1.02 g of Catalyst C was filled in a quartz tube having across-sectional area of 0.071 cm². 3 mL/min of an ethanol gas, 6 mL/minof nitrogen, and 3 mL/min of water as water vapor were fed, respectivelyinto the reaction tube and allowed to react under a gauge pressure of 0kPa, 100 kPa, 200 kPa, or 500 kPa at 450° C. A gas discharged from a gasexhaust port of the reaction tube was analyzed by means of gaschromatography to determine the conversion of ethanol and the yield ofpropylene. The results are shown in the following Table 4.

Example 5

The same operations as those in Example 4 were followed, except that 3mL/min of an ethanol gas, 3 mL/min of nitrogen, and 6 mL/min of water aswater vapor were fed, respectively into the reaction tube and that thereaction pressure was 500 kPa in terms of a gauge pressure, and theconversion of ethanol and the yield of propylene were determined. Theresults are shown in the following Table 4.

TABLE 4 Reaction Total flow Flow rate Flow rate H₂O/EtOH C3′ pressurerate of EtOH of H₂O ratio Conversion yield (kPaG) (mL/min) (mL/min)(mL/min) (mol/mol) (%) (%) Example 4 0 12 3 3 1 100 14.2 100 12 3 3 1100 17.4 200 12 3 3 1 100 19.3 500 12 3 3 1 100 23.6 Example 5 500 12 36 2 100 29.2

From Table 4, the higher the gauge pressure, the higher the C3′(propylene) yield was. Then, by increasing the H₂O/EtOH ratio, the C3′(propylene) yield became higher (Example 5).

Example 6 (1) Preparation of Catalyst F:

26.2 g of zirconium oxychloride octahydrate was dissolved in 60.1 g ofpure water, and 30% ammonia water was added until the pH of the solutionreached 3. The solution was stirred for one hour, affording a zirconiumoxide precursor-containing precipitate in a gel form. The zirconiumoxide precursor-containing precipitate was recovered from the solutionby means of filtration and washed with 200 mL of pure water. The washedzirconium oxide precursor-containing precipitate was heated in air at110° C. for 12 hours and then at 450° C. for 3 hours, thereby obtainingcalcined zirconium oxide. The calcined zirconium oxide was pulverizedand subjected to particle size regulation into a size of from 0.3 to 0.6mm by means of sieving. Thereafter, the resultant was rinsed with purewater and dried at 110° C. until the weight did not change, therebyobtaining dried zirconium oxide. The dried zirconium oxide waspulverized and subjected to particle size regulation into a size of from0.18 to 0.3 mm by means of sieving, thereby obtaining a catalyst forolefin production. This catalyst is hereinafter referred to as “CatalystF”. X-ray diffraction measurement found that Catalyst F was zirconiumoxide of a tetragonal crystal.

(2) Production of Propylene:

0.50 g of Catalyst F was filled in a quartz tube having across-sectional area of 0.071 cm². 3 mL/min of an ethanol gas, 6 mL/minof nitrogen, and 3 mL/min of water as water vapor were fed, respectivelyinto the reaction tube and allowed to react under a gauge pressure of200 kPa at 450° C. A gas discharged from a gas exhaust port of thereaction tube was analyzed by means of gas chromatography to determinethe conversion of ethanol and the yield of propylene. The results areshown in the following Table 5. In comparison with Example 4 usingCatalyst C which is zirconium oxide of a monoclinic crystal, in the caseof using Catalyst F which is zirconium oxide of a tetragonal crystal,the propylene yield was high while the catalyst amount was a half.

TABLE 5 Reaction Total flow Flow rate Flow rate H₂O/EtOH C3′ pressurerate of EtOH of H₂O ratio Conversion yield (kPaG) (mL/min) (mL/min)(mL/min) (mol/mol) (%) (%) Example 6 200 12 3 3 1 100 21.3

INDUSTRIAL APPLICABILITY

The present invention can be suitably utilized in the field of theproduction of chemical raw materials, in particular the field of theproduction of olefins capable of serving as raw materials forpolyolefins and olefin oxides.

1. A solid catalyst for producing, from an alcohol, an olefin whosenumber of carbon atoms is at least one more than the number of carbonatoms of the alcohol, wherein at least the surface of the catalyst issubstantially composed of zirconium oxide.
 2. The catalyst according toclaim 1, wherein the whole of the catalyst is substantially composed ofzirconium oxide.
 3. The catalyst according to claim 1, wherein thealcohol is ethanol, and the olefin is propylene.
 4. The catalystaccording to claim 1, wherein the zirconium oxide has a structure ofeither a tetragonal crystal or a cubic crystal.
 5. A method forproducing an olefin including an olefin formation step of forming, froman alcohol, an olefin whose number of carbon atoms is at least one morethan the number of carbon atoms of the alcohol, wherein in the olefinformation step, the alcohol is brought into contact with the catalystaccording to claim 1 at a temperature of from 300° C. to 700° C.
 6. Themethod for producing an olefin according to claim 5, wherein the alcoholcontains water in an amount of not more than 7 molar times the molarnumber of the alcohol.
 7. The method for producing an olefin accordingto claim 5, wherein the alcohol is brought into contact with thecatalyst at a gauge pressure of 50 kPa or more.
 8. The method forproducing an olefin according to claim 5, wherein the alcohol isethanol, and the olefin is propylene.
 9. A polyolefin produced using, asa raw material, an olefin produced by the method according to claim 5.10. An olefin oxide produced using, as a raw material, an olefinproduced by the method according to claim 5.